Oil supply systems for refrigerant compressors



Dec. 7, 1965 .1. L. DITZLER OIL SUPPLY SYSTEMS FOR REFRIGERANT COMPRESSORS Filed April 16, 1964 21 CENTRIFUGAL COMPRESSOR W 3,0 7| IO 35 36 E COMPRESSOR L 25 MOTOR 3WAY VALVE SUCTION CM LINE I 2 5 B 24 2| l2 I |3 OIL FILTER SOLENOID 22 DISCHARGE I5 19 LINE E OIL PRESSURE OJL E COOLER TANK PUMP J PM J 33 -32 3| IL {L I I Ll l 30 CONTROL 35 BOARD INVENTOR:

JOHN L.D|TZLER, BY W ATTORNEY United States Patent 3,221,984 OIL SUPPLY SYSTEMS FOR REFRIGERANT CGWRESSORS John L. Ditzler, Stauuton, Va., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Apr. 16, 1964, Ser. No. 360,400 4 Claims. (Cl. 230-207) This invention relates to oil supply systems for motordriven, refrigerant compressors having external, motordriven, oil pumps.

In one refrigeration system having a motor-driven, centrifugal compressor, and having an external, motordriven, oil pump for supplying oil to the bearings of the motor-compressor unit, it is the practice to energize the pump motor for a short period of time before the compressor motor is started, and to deenergize the pump motor shortly after the compressor motor stops. This provides oil to the bearings while the compressor and its motor are starting, and while they are coming to a stop. A disadvantage of such an oil supply system is that in case of a power failure, the oil pump motor will stop when the compressor motor stops.

An object of this invention is to provide an adequate supply of oil to the bearings of a compressor-motor unit while the motor and compressor are coming to a stop after a power failure.

This invention will now be described with reference to the annexed drawing which is a diagrammatic view of one embodiment of this invention.

DESCRIPTION A centrifugal, refrigerant compressor C is driven by an electric motor CM, the two being combined as a unit. The compressor C has an axial, gas inlet connected by a refrigerant line 11 to an evaporator which is not shown, and has a discharge gas outlet 12 connected by a refrigerant line 13 to a condenser which is not shown.

Lubricating oil is drawn from the bearings of the compressor C and the motor CM through a tube 14 by an oil pump P driven by an electric motor PM. The discharge side of the pump P is connected by a tube 15 to the inlet of an oil filter 16. The outlet of the filter 16 is connected by a tube 17 to the inlet of an oil cooler 18, the outlet of which is connected by a tube 19 containing a check-valve 20, to the lower portion of an oil pressure tank 21. The lower portion of the tank 21 is also connected by a tube 22 to the internal lubricating system of the compressor-motor unit. The upper portion of the tank 21 is connected by a tube 24 to a three-way valve 25 which is connected by a tube 26 to receive discharge gas from the compressor outlet 12, and which is connected by a tube 27 to the inlet 10 of the compressor. The valve 25 is adjusted by a solenoid 28.

The solenoid 28 is connected by wires 30 and 31 to wires 32 and 33 respectively, which connect the pump motor PM to a conventional control board CB. The compressor motor CM is connected by wires 35 and 36 to the control board. The control board is connected to electric power lines L1 and L2.

OPERATION In operation, just before the compressor motor CM is energized by the control board CB, the pump motor PM is energized by the control board to drive the pump P.

While the compressor is starting up, the pump P circulates oil through the tubes 14 and 15, the oil filter 16, the tube 17, the oil cooler 18, the tube 19 and check-valve 20, the oil pressure tank 21, the tube 22 and the bearings of the compressor-motor unit, and continues this circulation while the pump motor PM is energized. When the compressor motor CM is deenergized by the control board CB, the pump motor PM remains energized by the control board for a short time after the compressor motor CM is deenergized by the control board, so that oil is supplied by the pump P to the compressor-motor unit while it is coming to a stop. So far, the described operation is conventional except that the usual oil circuit does not include the oil pressure tank 21.

In the conventional system, when there is a power failure, the pump motor cannot continue to operate after the compressor motor is deenergized, so that there is inadequate lubrication during the time the compressor and its motor are coming to a stop. The coasting to a stop period may be twenty seconds or more due to the high speed of normal operation, and the fly wheel effect.

Using the controls of the drawing, the solenoid 28 is energized at the same time the pump motor PM is energized, and adjusts the valve 25 to connect the tube 24 with the tube 27. This connects the upper portion of the tank 21 with the inlet 10 of the compressor C, applying suction to the upper portion of the tank 21, causing the latter to fill with oil. When the pump motor PM and the solenoid 28 are deenergized, the solenoid 28 adjusts the valve 25 to connect the tube 24 with the tube 26. This connects the upper portion of the tank 21 with the outlet 12 of the compressor so that discharge gas from the compressor is supplied into the tank 21 above the oil level therein, forcing oil from the tank 21 through the tube 22 to the compressor-motor unit. The check-valve 20 prevents oil fiow through the tube 19 at this time. The oil so supplied from the tank 21 provides lubrication for thirty seconds, a period sufficient for adequate lubrication while the compressor and its motor are coming to a stop.

What is claimed is:

1. An oil supply system for a compressor-motor unit, comprising an oil pump, an oil pressure tank connected to the outlet of said pump, an oil return tube connected to said unit and to the inlet of said pump, an oil supply tube connected to the lower portion of said tank and to said unit, a valve, a third tube connecting said valve to the outlet of the compressor of said unit, a fourth tube connecting said valve to the upper portion of said tank, and means for adjusting said valve to connect said fourth tube to said third tube for supplying discharge gas from said compressor into the upper portion of said tank to force oil from said tank through said oil supply tube to said unit.

2. An oil supply system as claimed in claim 1 in which an electric motor is provided for driving said pump, in which a solenoid is provided for adjusting said valve, in which common means is provided for concurrently energizing said pump motor and said solenoid, said solenoid, when energized, adjusting said valve to disconnect said fourth tube from said third tube, and, When deenergized, adjusting said valve to connect said fourth tube to said third tube.

3. An oil supply system for a compressor-motor unit, comprising an oil pump, an oil pressure tank having its lower portion connected to the outlet of said pump, an

oil return tube connecting said unit to the inlet of said pump, an oil supply tube connecting the lower portion of said tank to said unit, a three-way valve, a third tube connecting said valve to the inlet of the compressor of said unit, a fourth tube connecting said valve to the outlet of said compressor, a fifth tube connecting said valve to the upper portion of said tank, and means for adjusting said valve to connect said fifth tube to said third tube or to connect said fifth tube to said fourth tube.

4. An oil supply system as claimed in claim 3 in which an electric motor is provided for driving said pump, in which a solenoid is provided for adjusting said valve, and in which common means is provided for concurrently energizing said motor of said pump and said solenoid,

said solenoid, when energized, adjusting said valve to con References Cited by the Examiner UNITED STATES PATENTS 7/1952 Haeberlein 230207 7/1952 Church 230207 X DONLEY J. STOCKING, Primary Examiner.

ROBERT M. WALKER, Examiner. 

1. AN OIL SUPPLY SYSTEM FOR A COMPRESSOR-MOTOR UNIT, COMPRISING AN OIL PUMP, AN OIL PRESSURE TANK CONNECTED TO THE OUTLET OF SAID PUMP, AN OIL RETURN TUBE CONNECTED TO SAID UNIT AND TO THE INLET OF SAID PUMP, AN OIL SUPPLY TUBE CONNECTED TO THE LOWER PORTION OF SAID TANK AND TO SAID UNIT, A VALVE, A THIRD TUBE CONNECTING SAID VALVE TO THE OUTLET OF THE COMPRESSOR OF SAID UNIT, A FOURTH TUBE CONNECTING SAID VALVE TO THE UPPER PORTION OF SAID TANK, AND MEANS FOR ADJUSTING SAID VALVE TO CONNECT SAID FOURTH TUBE TO SAID THIRD TUBE FOR SUPPLYING DISCHARGE GAS FROM SAID COMPRESSOR INTO THE UPPER PORTION OF SAID TANK TO FORCE OIL FROM SAID TANK THROUGH SAID OIL SUPPLY TUBE TO SAID UNIT. 